为具有RequestDispatcher和HttpServletRequest的类编写JUNIT测试用例

Question

我有一个类似于此的Filter类。

我的班级

@Override
public void doFilter(ServletRequest request, ServletResponse resp, FilterChain chain)
        throws IOException, ServletException {

    if (isMockAccountEnabled()) {
        HttpServletRequest req = (HttpServletRequest) request;
        String reqUrl = req.getRequestURI();
        ApiUserDetails userDetails = userBean.getUserDetails();
        HttpSession session = req.getSession();
        if (isThisTestAccount(reqUrl, session)) {

            log.debug("Entering Test acount flow for the request " + reqUrl);
            RequestDispatcher dispatcher = req.getRequestDispatcher("/mock/" + EnumService.returnMockService(reqUrl));
            dispatcher.forward(request, resp);
        }
    }
}

我想把JUNIT测试用例写进去。

我尝试过类似的事。

写的测试用例

@Mock
private FilterChain chain;


@InjectMocks
private MockAccountFilter mockAccountFilter = new MockAccountFilter();


MockHttpServletRequest request = new MockHttpServletRequest();
MockHttpServletResponse response = new MockHttpServletResponse();
MockHttpSession session = new MockHttpSession();
@Test
public void filterRequestMockFirst()
    throws Exception
{
    MockRequestDispatcher dispatcher =new MockRequestDispatcher("/mock/ABCTEST");
    when(request.getRequestDispatcher("/mock/ABCTEST")).thenReturn(dispatcher);
    request.setRequestURI("/check/employee/123456/false");
    mockAccountFilter.doFilter(request, response, chain);  
    Assert.assertTrue(request.getRequestURI().contains("/mock/ABCTEST"));

}

我是编写测试用例的新手。

我无法以适当的方式弄清楚它是怎么做的。

我收到错误消息

错误

when() requires an argument which has to be 'a method call on a mock'.

有人可以建议我为上述课程编写测试用例的最佳方式。